Then I would have felt sorry for the dear Lord. The theory is correct.
Notes from Wikiquote
As quoted in Reality and Scientific Truth : Discussions with Einstein, von Laue, and Planck (1980) by Ilse Rosenthal-Schneider, p. 74
Variants
"I would have felt sorry for the dear Lord! The theory is, of course, all right." Quoted in The Physicist's Conception of Nature by Jagdish Mehra (1979), p. 131. This source attributes it to a conversation with Ilse Rosenthal-Schneider, author of the book the previous version is from.